Question about prototype lightsabre hilt

Hello, in early artwork of the first Lego Star Wars wave, we can see these prototype lightsabre hilts in the pictures that differ slightly from the piece that was later released in sets (picture 1 and picture 2 both show the prototype pieces, picture 3 shows the ones we got in sets). The hilt design differs ever so slightly at the top of the hilt, with the prototype tapering down, whereas the released piece tapers upwards. I think I heard somewhere that they did this for stability. I was...